1. Field of the Invention
The present invention relates to a high frequency wave tuner module, and particularly to a high frequency wave tuner module which is provided with a shield cover to shield the interfering wave from outside.
2. Description of Related Art
In high frequency wave tuner module for receiving the signal of high frequency band such as the television tuner for the terrestrial digital broadcasting, the tuner for wireless LAN or a tuner for satellite radio or the like which is in used in the U.S., the module is structure by disposing the wiring patters such as the signal wire, the GND wire and the like and the circuit parts on both surfaces or on one surface of the single layer circuit board. Further, in recent years, a multiple-layer board which is formed by layering a plurality of boards is used as the circuit board for downsizing and thinning of the tuner module and improvement of the component mounting density of the tuner module (for example, JP5-327230A).
Moreover, in many cases, a shield cover for covering the board surface of the circuit board to shield the interfering wave from outside is provided in such circuit boards (for example, JP2006-101467A). Further, the GND of the circuit board is assured by connecting the shield cover with the GND of the board by soldering or the like.
In the manufacturing of the high frequency wave tuner module, the shield cover is attached to the circuit board as described in the above mentioned JP2006-101467A. Here, for example, the notches 102 are provided on the circuit board 101 as shown in FIG. 4A and the convex portions 105 are provided on the side walls 104 of the shield cover 103 at the positions corresponding to the above mentioned notches 102 as shown in FIG. 4B in order to correctly decide the position of the shield cover with respect to the circuit board.
As shown in FIG. 5, the position of the shield cover 103 is determined with respect to the circuit board 101 by inserting the convex portions 105 of the shield cover 103 in the notches 102 of the circuit board 101, and the four corners of the shield cover 103 are connected and fixed to the circuit board 101 by soldering or the like in a state where the four corners of the shield cover 103 are in contact with the circuit board 101 to form the high frequency wave tuner module 100.
The circuit board is usually manufactured by cutting one large board. When the notches are to be provided on the circuit board as described above, conventionally, the holes 107 which become the above mentioned notches 102 and the holes 108 which corresponds to the cut off portions of the four corners of the circuit board are perforated in the one large board 106 in advance as shown in FIG. 6, and the circuit boards having the notches are manufactured by cutting the board. Further, there is a case where the notches are formed after the circuit boards are cut out from the one large board.
However, there is a case where the low-temperature conferred ceramic (LTCC) having alumina as the base material is used for the single layer or the multiple-layer circuit board which is used for the high frequency wave tuner module. The ceramic material such as the low-temperature conferred ceramic is usually hard and the process of perforating the holes 107 and 108 in the board 106 and the process of forming the notches by scraping the circuit board as shown in FIG. 6 are not necessarily easy processes. The process of perforating a hole is easy before calcining because the material is soft. However, an accuracy of the size after calcining is hard to acquire. Further, the number of the processes increases because the process such as perforating holes in a large board or the like is needed, and the improvement of the productivity of the circuit board is prevented.
Moreover, when the convex portions of the shield cover are inserted in the notches of the circuit board, the circuit parts cannot be mounted on the portion 101a outside of the side walls 104 of the shield cover 103 within the circuit board 101 as shown in the high frequency wave tuner module 100 of FIG. 5, and the area on the circuit board 101 in which the circuit parts can be mounted is reduced. In contrary, when attempting to assure the area for mounting the circuit parts, the circuit board 101 needs to be made larger for the portion of the above mentioned outside portion 101a. Therefore, there is a problem that the downsizing of the high frequency wave tuner module is prevented.